I use a spreadsheet and on the Master Spreadsheet everything is put there in alphabetical order, so I can quickly find any street/area.
But each account is given a column with a code for example "NW Chepstow 1", and all the accounts I clean in this area have this code in that column.
To organise my work, I copy the Master Spreadsheet to a "Working Spreadsheet" file, and using the excell spreadsheet's 'Sort Function', I can quickly and easily sort my alphabetical spreadsheet into one by area. (I can also quickly 'sort' to find out who owes me too; or phone numbers; etc).
I then highlight the area I wish to clean and print it off.
Every week I e-mail the spreadsheet to myself, just in case the computer goes pear-shaped; 'cos I don't want to lose my customer database.
I have a bit of a background in administration, so maybe this is a little complex?